I have a project I wanted to log amp draws and voltage discharge curves for so I went looking for an Eagle Tree and saw that the company has gone out of business. Are their other companies that make stand a lone data loggers like the Eagle Tree v4? Im looking specifically for something that can be used on a Kraton 8S but Im also curious if there are any other companies that make any sort of data loggers at all too. Even if I cant find something big enough for my 1/5 Scale stuff I may down the road want something for smaller scale stuff too.

the higher end sanwa radios can log things to an SD card.
The modern generation of receivers expect a 'smart' ESC to supply all the data, but older receivers let you use discrete sensors.

They log voltage discharge curves and Amp draw? and are we talking high end radios for ground kits or air?

Have you looked at the data logging in the castle creations ESCs? I realise its not stand alone and they are not cheap ESCs but they seem very good. There us a dedicated thread in the speed running subforum over at the Arrma forum all about reading the logs.

Yeah, I even have a Castle ESC with a built in data logger but what Im trying to test is specifically with the Firma 160A ESC so I need a stand alone unit. Thx though

Im starting to get the impression that Eagletree was the only one that made dataloggers for RCs...

is a cheap Watt meter that should work well for you.

And how can you log data while driving?

Because of telemetry getting normal these days and ESC's becoming much advanced there is no need for a sepparate system. So I think you now have to dive into the world of the Arduino with which you can setup a simple data recorder using a SD card module, a voltage devider and an Hall current sensor.

Directly from the amazon page:

Not as ideal as the data you get from integrated telemetry, but enough info to extrapolate answers to OP's questions.

While many race oriented escs have some form of telemetry/data acquisition, the esc OP currently has does not. A stand alone system is less expensive and can easily be moved between vehicles of different size. Additionally, the stand alone system is much easier to monitor in the field as you don't have to hook up to an external device to see the data.

Novak used to make the Sentry data logger. You might try asking in the wanted to buy. I still use mine.